FIELD OF THE INVENTION
The invention relates to a method that makes it possible to adapt an injection timing which is specified for starting internal combustion engines, to currently prevailing variables of the ambient air.
In internal combustion engines, a depletion of the aspirated fuel-air mixture taken place upon starting, especially cold starting. That is because of the low fuel evaporation and marked moistening of the wall with the fuel. Moreover, at the low rpm of the starter, poor turbulence of the fuel particles is achieved. In order to compensate therefor, additional fuel is injected upon starting. There are major rpm fluctuations during the starting process, making the signal furnished by the air flow rate meter unreliable. Fixed injection timing values are therefore specified and stored in memory in a performance graph, as a function of the engine temperature or coolant temperature, as is described, for instance, in German Published, Non-Prosecuted Application DE 41 34 522 A1. Those injection timing values were ascertained for a certain air pressure (standard pressure), for instance on a test bench. However, if an air pressure other than standard pressure prevails at the actual moment of starting, then the wrong injection timing values are obtained. One result is overenrichment of the fuel-air mixture, for instance, if the vehicle is at higher altitudes.